High-Nickel, Acid & Corrosion-Resistant Bolts, Nuts, Studs, Screws & Washers — Engineered for Extreme Industrial Environments
Stainless Steel 904L fasteners are the preferred choice for engineers who don't want one bolt to fail in harsh chemical, marine or high purity applications. At Unifit Fastener, we produce and distribute UNS N08904 (WNR 1.4539) high-nickel high-molybdenum austenitic stainless steel bolts, nuts, studs, screws and washers that are resistant to pitting, crevice corrosion and stress-corrosion cracking beyond the standard 316L grades. Our SS 904L range is cold forged, precision threaded and tested to both the ASTM A193/A194 standards and the ASME SA193/SA194 and DIN/ISO standards – suitable for any application in a sulfuric acid plant, offshore platform, pulp/paper mill or food grade processing line. Each batch is delivered with a EN 10204 3.1 Mill Test Certificate, and custom sizes, coatings and packaging options are available upon request. In-house testing (PMI, IGC per ASTM A262, pitting per G48), transparent pricing and worldwide dispatch let procurement teams, EPC contractors and OEMs specify 904L with full traceability. Send your size list for a same-day quote.
Request a QuoteStainless Steel 904L is a super-austenitic, low-carbon stainless alloy (UNS N08904 / WNR 1.4539) enriched with high levels of nickel, chromium, molybdenum, and copper. The added copper improves resistance to sulfuric and phosphoric acids, while the low carbon content (max 0.02%) prevents carbide precipitation and intergranular corrosion during welding. The result is a non-magnetic, highly formable, and weldable fastener material suited to some of the harshest chemical and marine environments in industry.
| Identifier | Designation |
|---|---|
| UNS Number | N08904 |
| Werkstoff Number (DIN/EN) | 1.4539 |
| Old British (BS/EN) | 904S13 |
| Japanese JIS | SUS 890L |
| Common Trade Names | 904L, AISI 904L, INOX 904L |
| Parameter | Specification |
|---|---|
| Standard | ASTM A193 / A194, ASME SA193 / SA194, DIN, ISO, JIS, BS |
| Size Range — Bolts/Screws | M3 – M100 | 3/16" – 4" (custom sizes available) |
| Size Range — Nuts | M3 – M56 | 3/16" – 2" |
| Size Range — Washers | M3 – M56 | 3/16" – 2" |
| Length | 3 mm – 200 mm (custom up to 2000 mm on studs/rods) |
| Thread Types | UNC, UNF, BSW, BSF, Metric Coarse & Fine |
| Head / Drive Styles | Hex, Socket/Allen, Phillips, Slotted, Torx, Square, Button |
| Neck Type | Square, Round, Knurled, Hex, Triangular |
| Surface Finish | Passivated / Plain / Teflon / Zinc / Xylan / PTFE / Dacromet |
| Test Certificate | EN 10204 3.1 / 3.2 Mill Test Certificate |
| Manufacturing Process | Hot Forging, Cold Forging, CNC Machining, Wire Drawing |
| Standard Delivery Time | 7–20 days (stock items); 3–5 weeks (custom orders) |
| Element | Min | Max |
|---|---|---|
| Carbon (C) | — | 0.020 |
| Manganese (Mn) | — | 2.00 |
| Silicon (Si) | — | 1.00 |
| Phosphorus (P) | — | 0.045 |
| Sulfur (S) | — | 0.035 |
| Chromium (Cr) | 19.0 | 23.0 |
| Nickel (Ni) | 23.0 | 28.0 |
| Molybdenum (Mo) | 4.00 | 5.00 |
| Copper (Cu) | 1.00 | 2.00 |
| Nitrogen (N) | — | 0.10 |
| Iron (Fe) | Balance | — |
| Grade | Tensile Strength (MPa) min | Yield Strength 0.2% Proof (MPa) min | Elongation (% in 50mm) min | Hardness (HRB max) |
|---|---|---|---|---|
| 904L | 490 | 220 | 35 | 70–90 typical |
| Property | Value |
|---|---|
| Density | 8.00 – 8.05 g/cm³ |
| Melting Point | 1350°C (2460°F) |
| Elastic Modulus | 195 – 200 GPa |
| Thermal Conductivity (at 100°C) | ~13.0 W/m·K |
| Max Service Temperature (structural) | Up to 400°C |
| Grade | UNS No. | Old British (BS/EN) | Euronorm No. | Japanese JIS |
|---|---|---|---|---|
| 904L | N08904 | 904S13 | 1.4539 | SUS 890L |
| Industry | Typical Use Case |
|---|---|
| Chemical & Petrochemical Processing | Sulfuric/phosphoric acid handling equipment, reactors |
| Oil & Gas | Offshore platforms, pipelines, gas scrubbing plants |
| Marine & Shipbuilding | Hull fittings, deck hardware exposed to seawater |
| Pulp & Paper | Bleaching systems and chemical recovery units |
| Power Generation | Flue-gas desulfurization and cooling systems |
| Food & Pharmaceutical | Hygienic processing equipment requiring corrosion resistance |
| Fertilizer Industry | Acid storage and transfer fastening systems |
| Aerospace & Defence | Non-magnetic, high-strength fastening applications |
| Property | SS 316L | SS 904L | Duplex 2205 |
|---|---|---|---|
| Nickel Content | 10–14% | 23–28% | 4.5–6.5% |
| Molybdenum Content | 2–3% | 4–5% | 2.5–3.5% |
| Pitting Resistance | Moderate | High | Very High |
| Stress Corrosion Cracking Resistance | Low–Moderate | High | Very High |
| Magnetic Behaviour | Non-magnetic | Non-magnetic | Slightly magnetic |
| Typical Use | General corrosion service | Acidic/chemical environments | High-strength + corrosion service |
Stainless Steel 904L fasteners are widely selected for aggressive chloride environments because of their excellent resistance to pitting and crevice corrosion. One of the key indicators of this performance is the Pitting Resistance Equivalent Number (PREN).
The PREN is calculated using the following formula:
PREN = %Cr + (3.3 × %Mo) + (16 × %N)
With its high chromium and molybdenum content, SS 904L typically offers a PREN value of approximately 34–36, making it suitable for seawater service, desalination plants, chemical processing equipment, offshore platforms, and marine applications where superior corrosion resistance is required.
| Property | Typical Value |
|---|---|
| PREN Formula | %Cr + (3.3 × %Mo) + (16 × %N) |
| Typical PREN Value | 34–36 |
| Corrosion Performance | Excellent resistance to pitting and crevice corrosion |
| Recommended Applications | Marine, Chemical Processing, Offshore, Pulp & Paper, Desalination |
Correct tightening torque is essential to achieve the required clamping force without damaging the fastener or threads. The following values are provided as a general engineering reference for Stainless Steel 904L fasteners.
| Size | Recommended Torque (Nm) |
|---|---|
| M6 | 8–10 |
| M8 | 18–25 |
| M10 | 35–50 |
| M12 | 60–85 |
| M16 | 150–210 |
| M20 | 290–410 |
| M24 | 500–700 |
Note: These values are for reference only. Actual tightening torque depends on lubrication, thread condition, coating, bolt grade, and application requirements.
The following table shows the approximate weight of standard Stainless Steel 904L hex bolts for estimation and shipping purposes.
| Bolt Size | Approx. Weight (kg/100 pcs) |
|---|---|
| M6 × 30 | 2.2 |
| M8 × 40 | 4.8 |
| M10 × 50 | 8.9 |
| M12 × 60 | 15.2 |
| M16 × 70 | 30.8 |
| M20 × 80 | 56.5 |
| M24 × 90 | 95.6 |
Note: Actual weight may vary depending on thread length, dimensions, and manufacturing standards.
The price of Stainless Steel 904L fasteners depends on the product type, dimensions, manufacturing standard, surface finish, quantity, and destination.
| Product | Approximate FOB Price* |
|---|---|
| SS 904L Bolts | USD 8–18 per kg |
| SS 904L Nuts | USD 7.5–17 per kg |
| SS 904L Screws | USD 8.5–18.5 per kg |
| SS 904L Washers | USD 7–16 per kg |
| SS 904L Stud Bolts | USD 9–20 per kg |
*Prices are indicative only and are subject to fluctuations in raw material costs, order quantity, dimensions, and finish.
Need the latest Stainless Steel 904L Fasteners price? Contact our sales team today for a customized quotation, bulk order discounts, Mill Test Certificates (MTC), and worldwide delivery.
Unifit Fastener exports SS 904L fasteners worldwide via Mumbai and Kalamboli ports, with typical delivery windows below:
| Region | Typical Shipping Time |
|---|---|
| Middle East (UAE, Saudi Arabia, Oman) | 5–10 days |
| Southeast Asia (Singapore, Indonesia, Philippines) | 7–14 days |
| Africa (South Africa, Kenya, Nigeria, Egypt) | 18–30 days |
| Europe (Germany, Spain, Italy) | 20–30 days |
| North America (USA, Mexico, Canada) | 30–45 days |
SS 904L is used for fasteners and components exposed to highly corrosive acidic or chlorinated environments, including chemical processing plants, oil & gas equipment, marine hardware, and pulp & paper machinery.
No. SS 904L is a fully austenitic grade and is essentially non-magnetic in its annealed condition, making it suitable for sensitive instrumentation applications.
SS 904L contains significantly higher nickel (23–28%) and molybdenum (4–5%) than 316L, along with added copper. This gives 904L superior resistance to pitting, crevice corrosion, and stress corrosion cracking, especially in sulfuric and phosphoric acid environments.
Yes. Every SS 904L fastener order ships with a free EN 10204 3.1 Mill Test Certificate; 3.2 third-party certification is available on request for an additional charge.
We stock bolts and studs from M3 to M100 (3/16" to 4") and nuts/washers from M3 to M56 (3/16" to 2"), with custom sizes manufactured on request.
Available finishes include passivation, plain, Teflon, zinc plating, Xylan, PTFE, and Dacromet coatings depending on the application environment.
Get corrosion-resistant UNS N08904 fasteners with EN 10204 3.1 / 3.2 documentation, testing support and worldwide dispatch from Unifit Fastener.
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